Bottom Line:
Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode.Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters.This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.

Figure 1: Biomass composition of pennycress embryos at different stages of development. (A) Pictures of the embryos at different stages of development under a dissecting microscope. (B) Biomass accumulation rate of pennycress embryos. The orange circles, purple squares, green squares, red triangles, and blue triangles, respectively, represent the dry weight, the amounts of protein, fatty acid, starch, and cell wall accumulating in a pennycress embryo (n=4 biological replicates). (C) Biomass abundance in pennycress embryo. The purple, green, red, and blue bars are associated, respectively, with the percentage (w/w) of protein, fatty acid, starch, and cell wall characterizing a single embryo. Error bars are the SD of four biological replicates.

Mentions:
Biomass components are the final products of central metabolism, and their relative abundance reflects the allocation of carbon by primary metabolic pathways. In order to characterize the main carbon sinks and their accumulation rates, pennycress embryos were dissected at different stages (Fig. 1A) and then dried prior to biomass sequential extraction (Cocuron et al., 2014). Fatty acids, proteins, starch, and cell wall were quantified as described in the Materials and methods. A pennycress embryo grew on average 50.2 μg (DW d–1 (R2=0.97), accumulating fatty acids, protein, cell wall, and starch with the rates of 16.8 (R2=0.94), 19.3 (R2=0.95), 12.8 (R2=0.95), and 1.9 μg d–1 (R2=0.97), respectively (Fig. 1B). The protein:fatty acid ratio in pennycress embryos dropped from 8.0 at 11 DAP to 1.2 at 21 DAP, indicating an increase in oil accumulation (Fig. 1C). Fatty acid composition varied across developmental stages to reach a steady state at 15 DAP. Indeed, linoleic acid (C18:2) was found to be the most abundant at 11 DAP (33.8±1.5) whereas erucic acid (C22:1) was under the limit of detection. Then, at 19 DAP, erucic acid became the most abundant fatty acid, reaching a plateau at 36% (Supplementary Fig. S2 at JXB online).

Figure 1: Biomass composition of pennycress embryos at different stages of development. (A) Pictures of the embryos at different stages of development under a dissecting microscope. (B) Biomass accumulation rate of pennycress embryos. The orange circles, purple squares, green squares, red triangles, and blue triangles, respectively, represent the dry weight, the amounts of protein, fatty acid, starch, and cell wall accumulating in a pennycress embryo (n=4 biological replicates). (C) Biomass abundance in pennycress embryo. The purple, green, red, and blue bars are associated, respectively, with the percentage (w/w) of protein, fatty acid, starch, and cell wall characterizing a single embryo. Error bars are the SD of four biological replicates.

Mentions:
Biomass components are the final products of central metabolism, and their relative abundance reflects the allocation of carbon by primary metabolic pathways. In order to characterize the main carbon sinks and their accumulation rates, pennycress embryos were dissected at different stages (Fig. 1A) and then dried prior to biomass sequential extraction (Cocuron et al., 2014). Fatty acids, proteins, starch, and cell wall were quantified as described in the Materials and methods. A pennycress embryo grew on average 50.2 μg (DW d–1 (R2=0.97), accumulating fatty acids, protein, cell wall, and starch with the rates of 16.8 (R2=0.94), 19.3 (R2=0.95), 12.8 (R2=0.95), and 1.9 μg d–1 (R2=0.97), respectively (Fig. 1B). The protein:fatty acid ratio in pennycress embryos dropped from 8.0 at 11 DAP to 1.2 at 21 DAP, indicating an increase in oil accumulation (Fig. 1C). Fatty acid composition varied across developmental stages to reach a steady state at 15 DAP. Indeed, linoleic acid (C18:2) was found to be the most abundant at 11 DAP (33.8±1.5) whereas erucic acid (C22:1) was under the limit of detection. Then, at 19 DAP, erucic acid became the most abundant fatty acid, reaching a plateau at 36% (Supplementary Fig. S2 at JXB online).

Bottom Line:
Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode.Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters.This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.